Cable box extremely slow to do anything

Intermittently, and becoming more frequently, the cable box is extremely slow -- does not respond to the remote or when it does it takes a few minutes. I can't describe what it's doing exactly. I've put fresh batteries in the remote, and it didn't make a difference. Happens on the main X1 box and the secondary box in my brother's room. We've unplugged the box several times, waited, plugged it back in, and we're still waiting for it to respond. Tried the reset feature in Troubleshooting and got the message it couldn't reset the box because it wasn't connected, when clearly it is. Tried the reset through the Chat feature and it said it would take 10 minutes -- we gave up after 30. Unplugged it again, plugged it back in -- nothing. Ideas, anyone?